Isolation and engine speed limit controller



June 10, 1958 R. M. HENDERSON 2,838,298

ISOLATION ANO ENGINE SPEED LIMIT CONTROLLER Filed June 4, 1954 ABYQQL. 4.0%

United States Patent O ISOLATIN AND ENGINE SPEED LIMIT CONTROLLER Robert M. Henderson, Williams Bay, Fairbanks, Morse & Co., Chicago, Illinois Wis., assignor to Ill., a corporation of This invention relates to an isolation and engine speed limit controller for engine systems, and in particular relates to an isolation and engine speed limit controller for a diesel-electric locomotive system.

In the conventional diesel-electric locomotive system a throttle switch controls energization of a plurality of governor solenoids in various combinations depending upon the positionment of the throttle and these solenoids operate, through the governor, to determine the speed of operation of the diesel engine. Thus by way of example, the master throttle may be provided with stop and idle positions and positions representing eight different speeds, the latter positions being referred to as notches 1 through 8. When the throttle switch is placed in the stop position the diesel engine is stopped by energizing one of the solenoids, and when the throttle is in the idle position the solenoids are all deenergized to cause, through governor control of the fuel racks, diesel engine operation at an idling speed, as for example 300 R. P. M. As the throttle controller is moved into the various notches l through 8, the solenoids are energized and deenergized in appropriate combinations to condition the governor and adjust the fuel racks to cause the diesel engine to operate at speeds dependent upon the particular notch in which the throttle is disposed. By Way of example the throttle, solenoids, governor and fuel racks may be arranged to provide a diesel engine speed of 300 R. P. M. in the notch l position of the throttle switch, and the engine speed will incrementally increase as the controller is moved to the higher numbered notches until in notch 8 the diesel engine speed is 860 R. P. M.

It is also conventional in diesel-electric locomotive systems to operate two or more locomotives together, and this is called multiple-unit (MU) operation. When locomotives are operated MU, the throttle switches or" the diiterent units are electrically connected so that the operation of one throttle also operates the governor solenoids of the other locomotive units in the same manner in which it operates the solenoids of the unit wherein the throttle controller is located. Thus in MU operation, as the throttle in the locomotive from which the multiple units are being controlled is placed in notch number 8, the solenoids associated with each governor will cause through the governor, an adjustment of the fuel racks of the associated diesel engine, so that all diesel engines are operated at 860 R. P. M., and correspondingly the diesel engines will be similarly driven at the same speeds for various other throttle controller positions.

In the novel system of the present invention an isolation and engine speed limit controller or switch is provided. In particular this controller controls, conjointly with the master throttle, the energization of the governor solenoids. The isolation and limit control switch is a multiposition switch, which either maintains certain of ICC the governor solenoids in a deenergized state independently of the master throttle, or enables certain of the governor solenoids to be energized by master throttle operation depending upon the particular positionment of the isolation and limit controller. For example, when the isolation and speed limit control is in a position to isolate the diesel engine from the control of the master throttle, all of the governor solenoids are retained in a deenergized state independently of the master throttle so that the engine will operate only at its idling speed. Likewise when the limit controller is positioned to limit diesel engine speed to the speed corresponding to 5th notch positionment of the master throttle, certain of the solenoids are retained in a deenergized state so that even with the throttle in the 6th, 7th or 8th notch the diesel engine speed will not exceed its normal 5th notch speed. Also with the limit switch in the run 6 or run 7 position i. e., the positions which limit the engine speed to the speed determined by notch 6 or notch 7 of the master throttle, certain of the governor solenoids are retained in a deenergized state while certain other solenoids may be energized by the master throttle. Thus an upper engine speed limit is imposed on the engine even if the throttle is placed in a notch which would otherwise cause an engine speed greater than the limit.

An object of this invention is to provide an engine speed limiting control, which is operable to limit engine speed irrespective of master throttle positionment.

Another object of this invention is to provide an isolation controller, which causes engine operation at an idling speed independently of master throttle controller positionment.

A further object of this invention resides in the provision of an isolation and speed limit controller for a diesel-electric locomotive system, wherein the controller operates conjointly with the master throttle to energize or prevent energization of governor solenoids to either isolate the `diesel engine from control by the master throttle or establish a maximum engine speed even if the throttle is positioned to call for higher engine speed operation.

A still further object of this invention is the provision of an isolation and speed limit controller for dieselelectric locomotives that are operated multiple-unit, wherein the controller enables one locomotive to be isolated from throttle control or have a maximum speed limit imposed thereon independently of throttle positionment at the control station from which the multipe-units are operated.

These and other objects and advantages will become more readily apparent as the description proceeds and is read in conjunction with a single `drawing attached hereto, which shows a schematic diagram of two diesel-electric locomotive systems connected for MU operation, each system including the novel isolation and engine speed limit controller.

It has been found that during operation of dieselelectric locomotives, it is frequently desired or required that the diesel engine be isolated from throttle control i. e., throttle positionment does not iniiuence engine speed, or a maximum speed limit must be imposed on the diesel engine even if the throttle is accidentally or intentionally positioned so as to require higher engine speed operation. For example, in servicing the locomotive or in many other cases it is necessary to isolate the diesel engine so that it will remain at idling speed regardless of throttle position. The reasons for limiting engine speed are numerous, but by way of example, two broad classes of difiiculties that will necessitate limiting engine speed are,

first, difficulties in the mechanical part of the system and, second, difficulties in the generator or electrical portion of the system. With the latter it is necessary to limit engine speed so as to limit generator voltage, while with the former engine speed is limited to protect against mechanical failures. Thus engine speed may be limited by setting the speed limit controller to prevent ground relay action in the event of moisture grounds or to reduce engine load temporarily in the event of a hot engine alarm. Likewise engine speed may be limited in case of cooling system failure, lube oil filter failures or during a period in which a new locomotive is being tested.

For maximum efciency, utility and flexibility in multiple-unit operation, it is essential to provide an arrangement whereby any locomotive can be isolated from p throttle control and, furthermore, whereby any locomotive may have a maximum speed limit placed on the diesel engine of that locomotive without affecting any other locomotive units. For example, one unit may be required, for any of the several reasons hereinbefore described or for a plurality of other reasons, to be operated at its idling speed, to be stopped altogether, or to be limited to speeds of operation below the highest speed setting of the throttle controller. To accomplish this, the isolation and speed limit controller of the affected locomotive is disposed in the isolation position or in one of the several speed limit positions, and the positionment of this particular isolation and speed limit controller will have no effect on the other locomotives even though these other locomotives are otherwise under control of all the throttles of the units.

Referring now to the attached drawing for a better understanding of the present invention, shown thereon in schematic form are two identical diesel-electric locomotive systems designated by numerals and l2. Systems 10 and 12 are connected for multiple-unit operation through conventional MU connecting cables, partially indicated by wires ld, 16, i8 and 2i). Since the dieselelectric systems l0 and l2 are identical, like numerals have been used to designate like parts in the two systems.

in the diesel-electric system itl, diesel engine 22 drives a main generator 24 which supplies power to a plurality of traction motors 26 for propelling the locomotive. The diesel engine also drives an auxiliary generator 2% which provides excitor field current for main generator 2/5 and produces a voltage for the control circuit between output leads 3i) and 32.. The speed of operation of diesel engine 22 is determined by the setting of fuel racks 34, the fuel rack settings being effected by governor 36 in the conventional manner. Governor 36, which by way of example may be the Woodward type PG governor produced by Woodward Governor Co. of Rockford, illinois, determines engine speed in accordance with the energized or deenergized condition of governor solenoids A, B, C, and D, as will now be explained.

While the novelty of the present invention does not depend upon the particulars of the governor or upon the particular combinations in which the solenoids are energized to provide various speed settings of the governor, it is helpful in understanding the present invention to describe specific combinations of solenoid energizaticn. By way of example it will be assumed that the diesel engine is to operate at 8 different speeds, and is to have an idling speed the same as the lowest running speed. In the table below the solenoids that are energized to condition the governor for engine operation at any particular speed, are indicated by placing an asterisk under the solenoid indicating letter and on a horizontal line with the particular engine speed. Thus for the governor to operate the diesel engine at 300 R. P. M., none of the solenoids are energized, while to operate the engine at 540 R. P. M. solenoids A and C are energized. Likewise to operate at the maximum speed of 860 R. P. M. solenoids A, B and C are energized.

4 Table 1 Solenoids Energized R. P. M. Engine Speed The energization of the governor solenoids is controlled by a master throttle switch generally indicated at 3S. The lower end of solenoids A, B, C and D are connected to output lead 32 of auxiliary generator 2S, while the upper end of the solenoids are connected respectively to leads 42, 4-4, 46 and 48. Lead 30 of the auxiliary generator is connected by conductor 5t) to a plurality of xed contacts 52, S4, 56 and 5S of master throttle 38. Opposed to fixed contacts S2, 54, 56 and 5S are fixed contacts 60, 62, and 66. Master throttle 3&5, is, by way of example,

o schematically shown as a drum type switch having a movable contact plate 68 the circumference of which is indicated by lines 7i). As the throttle handle (not shown in the drawing) is moved, contact plate 68 is translated upwardly or downwardly in the drawing. As shown in the drawing the contact plate is disposed in its idle position i. e., the throttle lever or handle is in the idle position. The cross marks on plate 68 which are vertically aligned with the opposed fixed contacts serve to indicate that the opposed lixed contacts are electrically connected together when plate 68 is moved to a position disposing the cross mark between the opposed contacts. Thus in the idle position as shown in the drawing, opposed contacts 52 and 6), S-- and 62, 56 and 64, and S8 and 66 are disconnected so that the control voltage of conductor 56 is not present on leads 69, 71, 72 and 74, connected respectively to contacts tl, 62, 64 and 66. Leads 69, 71 and 74 are connected, respectively, to solenoids D, C and A through isolation and limit controller 4t), while lead 72 is connected to solenoid B independently of controller d0.

The table shown below graphically illustrates the operation of throttle 33. An asterisk is placed beneath the designation of leads 69, 7l, 72 and 74 and horizontally aligned with the appropriate numeral in the left hand column indicating the throttle setting, whenever the control voltage from conductor 5t) is impressed on leads 69, 7i, 72 and '74 through the opposed contacts associated with these leads. As an example in reading the table, when the throttle controller is in position number 4, the

As indicated, isolation and limit controller 4u is interposed in circuit with solenoids A, C and D and as also indicated in the drawing, lead 69 is connected to iixed contact 76, lead 71 to contact 7S and lead 74 to contact 'of controller 40. Opposed to contacts 76, 7S and 80 of controller 40, which is also a drum type switch, are

xed contacts 82, 84 and 86, which are respectively connected to coils D, C and A by leads 48, 46 and 42. Contact plate S8 of controller 49 is adapted to be manually positioned by a hand lever (not shown in the drawing) so that the opposed contacts of controller will be either closed or open depending upon the positionment of contact plate 88. Thus the connection of leads 69, 71 and 74 to solenoids D, C and A, respectively, will depend upon the position in which contact plate 88 is disposed. The table below indicates by an asterisk when opposing contacts 76 and S2, 78 and 84, and 8G and S6 are connected together in various positionments of the controller 40.

Table 3 Opposing Contacts Closed Isolatlon and Lrmlt Controller Position Hence it will appear from the description hereinbefore given, that the energization of solenoids A, C and D will depend not only upon the positionment of throttle 38 but also upon positionment of controller 40. When controller 40 is disposed in a position corresponding to run 8, i. e. where no engine speed limit is established by controller 40, solenoids A, C and D are electrically connected to fixed contacts 66, 62 and 6i) of throttle 38 (solenoid B also being connected to xed contact 64 of throttle 3S), and the solenoids are energized or deenergized entirely dependently upon the positioninent of the throttle. Table number 4 below indicates which of the solenoids are energized when controller 40 is in the run S position and when the throttle is in its several positions.

Table 4 R. P. M. Engine Speed Solenoids Energized Throttle Positions The manner in which controller 40 serves to limit maximum engine speed will now be described. In order to condition the governor 36 to operate diesel engine 22 at an engine speed higher than the 5th notch throttle setting speed, it will appear from table number 4 that one or the other or both of the solenoids A and C must be energize. It Will also appear from the drawing that when controller 40 is disposed in its run number 5 position, solenoids A and C cannot be energized regardless or throttle positionment, since opposed contacts 78 and 84 and opposed contacts 80 and 86 of controller 40 are retained in an open condition. Thus as is presently explained diesel engine 22 will not operate at a speed higher than the 5th throttle notch speed (620 R. P. M.) even if throttle 38 is positioned to operate the engine at the 6th, 7th, or 8th notch speeds while the controller is in its run 5 position.

As is Well known in the Woodward type PG governor, the energization of each solenoid A, B, C and D individually, may cause a predetermined change in governor spring tension so as to cause a predetermmed change 1n the operating engine speed. As will appear from table number 4 above, when solenoid A is energized, engine speed increases in the example herein used from 300 to 380 R. P. M. When solenoid C alone is energized, the speed of engine operation is 460 R. P. M., an increase of 16() R. P. M. over the idling speed. Likewise the energization of solenoid B alone would condition the governor to operate the engine at 620 R. P. M., an increase of 320 R. P. M. from the idling speed. Also as indicated in table number 4, energizing solenoid D alone causes the governor to stop the engine. With these relationships in mind, it appears that energizing solenoid A increases engine speed R. P. M., energizing solenoid C increases engine speed R. P. M., and energizing solenoid B increases engine speed 240 R. P. M. By governor construction energizing solenoid D may be said to decrease engine speed by 160 R. P. M. when it is operated in combination with other solenoids. lf the solenoids are energized in various combinations, the total effect on engine speed may be determined by simply adding the number of R. P. M.s corresponding to the individual energization of the solenoids at the same time treating the 160 R. P. M. decrease of solenoid D as a negative number. Thus if solenoids A and C are energized, the engine speed will be 54() R. P. M., an increase of 240 R. P. M. In other words 8() R. P. M., which represents the increase in engine speed over the idle speed due to energizing solenoid A, plus 160 R. P. M., which represents the increase in engine speed due to the energization of solenoid C, is equal to the total increase in engine speed, 240 R. P. M. Similarly, energizing solenoids A and B will increase the engine speed from its idle speed by 40() R. P. M. (804-320). Since energizing solenoid D decreases engine speed, if solenoids C and D are energized at the same time the engine speed will remain at its idling speed, because energizing solenoid C attempts to increase the speed 160 R. P. M. While energizing solenoid D attempts to decrease the engine speed 160 R. P. M., to produce zero net change in engine speed. Likewise, concurrently energizing coils B and D increases the speed 160 R. P. M., i. e. 320 minus 160.

Bearing in mind the effect of energizing the solenoids A, B, C and D in the various combinations as described above and considering the eiect of placing controller 40 in its run number 5 position to prevent solenoids A and C from being energized, it will be seen that the throttle 38 can still be moved to its stop position to thereby energize coil D and stop the engine since contacts 76 and 82 of controller 40 are closed. When throttle 38 is moved to its idler or number l position all of the solenoids are deenergized and governor 36 maintains diesel engine 22 at its idling speed. When the master throttle 3S is moved to its number 2 notch, contacts 58 and 66 are connected together, but since contacts 80 and 86 are open, solenoid A remains deenergized and the engine continues to operate at its idling speed even though the throttle is in the number 2 position. When the throttle is placed in the number 3 notch, contacts 54 and 62 of throttle 38 are closed, but since contacts 78 and 84 remain open solenoid C is not energized and the engine still operates at its idling position. Likewise, even though in the number 4 notch the throttle causes voltage to be supplied from conductor 5() to leads 71 and 74, the controller 40 retains solenoids A and C deenergized, and the engine continues to operate at its idling speed. Thus when the throttle is in the second, third and fourth positions solenoids B and D are not energized by so positioning the throttle, solenoids A and C are deenergized by controller 40 and Itherefore all solenoids remain deenergized to cause engine operation by the governor at idling speed. As indicated in table number 4, when the throttle is moved to number 5 notch position, solenoids B, C and D would be energized but for the intervention of controller 4t) in series with solenoid C. In the run number 5 position, controller 40 retains solenoid C deenergized and therefore only solenoids B and D are energized. As previously discussed, energizing solenoid B causes an increase in engine speed of 320 R. P. M. while energizing solenoid D tends to cause a decrease of 160 R. P. M. Thus in this condition (notch throttle positionment and run nurnber 5 limit switch positionment) the engine operates at 460 R. P. M. Similarly, in notch 6 positionment of throttle 38, the throttle tends to energize solenoids A, B, C and D, but solenoids A and C are retained in a deenergized state by'controller 40 so that the net effect on speed is to increase the speed 160 R. P. M. (320 minus 160) for an operating speed of 460 R. P. M. When throttle 38 is in the 7th notch, solenoids B and C would be energized except for controller 40 which retains solenoid C inoperative. Thus solenoid B alone is effective and the engine speed increases 320 R. P. M. for an operating speed of 620. Likewise in 8th notch throttle position, only solenoid B is energized, since controller 4t) retains solenoids A and C inoperative, for engine speed operation of 620 R. P. M. Hence it will be seen that even though throttle 3S is positioned in notches 6, 7 or 8,Y with controller 40 in its run 5 position, the controller limits the maximum engine speed to the ordinary 5th notch engine speed of 62() R. P. M. The effect of positioning controller 4@ in run 5 position is briefly demonstrated in Table 5 below.

Table 5 [With controller 40 in run 5 position] Engine .Speed is (R. P. M.)

When Throttle 38 Is In Notch When controller 40 is disposed in run 6 position, opposed contacts '78 and 84 remain open so that solenoid C cannot be energized, while opposed contacts 80. and S6 are closed so that solenoid A is freely energizable under the control of throttle 38 and contacts 7 6 and 82 4are closed so that solenoid D is also freely energizable. Table number 6 set forth below she-ws the net effect of positioning isolation and limit control 4Q in its run 6 position, and it will be noted that the engine speed does not exceed 700 R. P. M. (normal engine speed for notch 6 positionment of throttle 33). lievedthat the effect of positioning controller 40 in run 6 will be clear. However an example of its effect will now be described. Assuming that throttle 38 is in the num- 'oer 8 notch and controller 46 is in run 6 position, solenoid i5 will be energized directly from the throttle, solenoid A will be energized through contacts Sti and 86 of the controller, and solenoid C is not energized because opposed `contacts 78 and 84 of controller 4t? remain open. As previously indicated when solenoid A and D are energized the engine speed will be 700 R. P. M.

Table 6 [With controller 40 in run 6 position] Engine Speed is (R. P. M.)

When Throttle 38 Is ln Notch From the foregoing description,-it is be- Table number 7 below shows the effect on engine speed of positioning controller 4U in run 7 position.

Table 7 [With controller 40 in run 7 position] When Throttle 38 Is In Notch u noids are energized in accordance with throttle positionment.

VWhen diesel engine 22 is to be isolated from throttle switch 38, controller 4t) is placed in its isolation position. ln this position it will be noted that opposed contacts 76 and 82, 78 and 84, and 80 Vand 86 are all opened so that solenoids A, C and D cannot be energized regardless of throttle positionment. When the diesel engine is isolated, the engine is to be driven at the idling speed, or 300 R. P. M. in the example used herein. `lt will be seen from table number 4 that all of the solenoids must be deenergized to condition governor 36 to drive engine 22 at the idlingV speed. In order to retain solenoids A, B and C in condition such that they are incapable of energization byY throttle 38, another pair of opposed contacts and 92 are provided on controller 40. Contact 90 is connected to control voltage lead 30, while contact 92 is connected through a relay coil 94 with the other control voltage lead 32. Thus when the contacts 90 and 92 are connected together, coil 94 is energized to close contacts 96, 97S and lili) in leads 42, 44 and 46. Contacts 90 and 92 of con-V troller 40 are arranged to be closed Vat all times except when the controller is disposed Vin the isolation position. Thus contacts 96, 93 and 100 are normally closed so that solenoids A, B and C are energizable, but when the controller is placed in isolation position, contacts 96, 98 and Ilt open to deenergize solenoids A, B and C, while at the same time, opposed contacts '76 and 82 of controller 40 are opened to deenergize solenoid D. Thus all solenoids are deenergized and the engine 22 operates at its idling speed.

Some of the most important advantages of the novel isolation and speed limit controller of the present invention are realized when locomotives are operated MU. In the drawing the two identical diesel-electric locomotive systems are connected for MU operation, and as indicated the leads 14, 16, 1S and 20 connect the two throttles 33 so that the engine speed of both engines 22 can be controlled from one or the other of throttles 38. However, limit controllers 40 are effective such that each controls only its own engine system. Thus when the controller 40 of locomotive system 10 is set in run 5 position and the controller 4t) of locomotive system l2 set Yin run 8 position, engine 22 of system l0 will not exceed its notch 5 speed of 620 R. P. M. even through engine 22 of system 12 can be driven at the notch 8 speed of 860 R. P. M. by placing either throttle 33 in its notch 8 position. By way of further example, if controller 40 of system it) is placed in its isolation position, engine 22 of that system will idle at 300 R. P. M. even though engine 22 ofrsystem 12 may be driven at any desired speed by placing controller 40 9 of system 12 in -an appropriate run position and by operating one or the other of the throttles. In other words, the isolation and engine speed limit switch or controller of one system does not affect the other system connected in MU.

Having now described the invention, what is claimed is:

1. In a multiple-unit locomotive system having a plurality of locomotive units, an engine in each unit, an adjustable engine speed controlling governor for each engine having adjustment eecting solenoids energizable in predetermined combinations to adjust the governor for determining engine operation at predetermined speeds, energizing circuit means for the solenoids of each governor, a throttle switch in the solenoid circuit means of each governor operable to effect energization of the solenoids in said predetermined combinations, electrical connections interconnecting said energizing circuit means and throttle switches of the locomotive units whereby operation of the throttle switch in any one of the locomotive units will effect energization of the governor solenoids in all of the units, and a controller in each locomotive unit connected in the energizing circuit means between the throttle switch and governor solenoids in such unit, operable for rendering certain of the associated solenoids incapable of energization by the throttle switch in any of the units, said controller in each unit being incapable of effecting throttle switch energization control of the governor soleniods in any other unit.

2. In a control system for an internal combustion engine having an adjustable governor including governor adjusting solenoids effective through selective energization thereof for adjusting the governor to determine engine operation at correspondingly different predetermined operating speeds, the combination with the governor solenoids, of solenoid energizing circuit means including a throttle switch for determining solenoid energization selectively according to throttle switch actuation, and controller means arranged in said circuit means between the throttle switch and solenoids, said controller means being selectively settable to condition the circuit means for limiting throttle switch energization control of the solenoids variably in accordance with settings of the controller means.

3. In a control system for an internal combustion engine having an adjustable governor including governor adjusting solenoids eective through selective energization thereof for adjusting the governor to determine engine operation at correspondingly dierent predetermined operating speeds, the combination with the governor solenoids, of solenoid energizing circuit means including a throttle switch for determining solenoid energization selectively according to throttle switch actuation, and selectively settable controller means arranged in said circuit means between the throttle switch and solenoids, said controller means in an initial setting thereof rendering the throttle switch ineffective to determine energization of the solenoids, the controller means in a terminal setting thereof conditioning the circuit means for permitting throttle switch determination of solenoid energization selectively according to throttle switch actuation, and the controller means in settings intermediate said initial and terminal settings, conditioning the circuit means for limiting throttle switch energization control of the solenoids variably in accordance with intermediate settings of the controller means.

References Cited in the tile of this patent UNITED STATES PATENTS 1,866,347 Crocker July 5, 1932 2,640,550 Knapp et al. June 2, 1953 2,650,580 Moulton Sept. 1, 1953 

